The present invention concerns a dual-fuel fuel injector including a first injector unit for a first operating mode using a first main fuel and a second injector unit for a second operating mode using a second main fuel wherein the injector includes an injector reservoir.
In connection with the use of dual-fuel fuel injectors, in particular in large motors, there is always the question of how to arrange on the injector in addition to a storage volume for liquid fuel also a large storage volume for gaseous fuel in taking into consideration the respective installation conditions in particular since each may be an individual high pressure reservoir. Large gas reservoir volumes are advantageous in order to keep a pressure loss during the gas injection process low, in particular because of the large pressure differential change between gas and combustion chamber pressure occurring during the compression stroke, it is difficult enough to inject the desired gas volume into the combustion chamber.
If it is constructively impossible to incorporate the gas and liquid fuel reservoirs required for a 100% engine load into an injector compromises must be accepted regarding the sizes of the reservoirs. With a motor which is designed for gaseous fuel operation as well as for liquid fuel operation, those consequences must be accepted either for both types of operation or—to a much larger extent—in connection with only one type of operation. This however may result in a particular mode of operation with limited power output.
Based hereon, it is the object of the present invention to provide a dual-fuel fuel injector which is suitable to provide the required reservoir needs with only relatively small space requirements.